Despite the trend towards multiple devices per person, many people still store all their important files on a single PC or storage device, and donít have access to them from their other devices. These files are associated with a ďplaceĒ Ė a desktop PC, a laptop, or a USB key. If you donít have access to that place, you donít have access to your documents or photos. Not only is accessing your files difficult (or sometimes impossible), sharing them with someone on a different network can be just as tricky.
Extending "Windows 8" apps to the cloud with SkyDrive - Building Windows 8 - Site Home - MSDN Blogs